Hyper Suprime-Cam (HSC)

Information for S21B applicants

  Schedule of HSC runs in S21B
  • HSC will not be available for about two and half months while the overhaul work of the top unit exchanger is in progress (see also S21B Call for Proposal announcement).
  • No HSC run in early August due to maintenance of the telescope facility.

  Filter set
The NB391, NB395(1), and NB506 filters are newly opened from S21B. If you would like to use these and NB497 filters, you must obtain an approval from filter developer team in advance of the proposal submission. HSC applicants must explicitly describe the filters they intend to use in the "Instrument Requirements" section of the application form, where the desired set as well as the minimum acceptable set should be clearly specified.

(1) The NB391 and NB395 filters are open with shared risk. There is a possibility that NB395 is not available in S21B if it is not confirmed to work properly in the filter exchange unit. In this case, the open of NB395 as well as NB391 will be postponed because the two filters need to be open in the same semester.

  Default observation mode
Queue mode is the default observing mode for the Normal, Intensive, and Filler programs (see the detail information at the "HSC Queue Mode Webpage"). Applicants wishing a classical mode observation with HSC have to describe why the classical mode is preferred to the queue mode in "Scheduling Requirements" section of the application form. Without any convincing reason, the observation mode may be changed from classical to queue. Note that a proposal requesting the NB387, NB391, and NB395 filters must be submitted as a classical mode program.

  Observations for HSC-SSP fields
HSC applicants requesting to observe the same fields as targeted in the HSC-SSP (Subaru Strategic Program) are obliged to clarify the reason for doing so (e.g., how the scientific aim is different from that of SSP).

  "No-Additional-Target" policy
Requesting additional targets for filling dead time (a.k.a. "Sukima time"), when there is no planned target on the night sky, is not allowed for any HSC observations. "Sukima time" will be exploited as effective as possible depending on the situation (observing priority: (1) observations of standard stars, (2) queue-mode observations for Grade A/B programs, (3) observing applicant's back-up targets, and (4) queue-mode observations for Grade C and F [Filler] programs).

  No service programs
Service observations are not available for HSC.

Last update: February 3, 2021

Advice for observers of HSC S19A/S19B programs:

  It was confirmed that HSC images had suffered from two kinds of problems since late February 2019.
  Please be sure to read the following announcements for reduction of HSC data obtained in the corresponding periods.
  1.   Shadow due to a lens stain   ( 2019/2/27–10/4 UT )

  2.   Arc-shaped ghost due to stray light from the dome inside   ( 2019/2/27–11/6 UT )

Last update: November 15, 2019



The Hyper Suprime-Cam (HSC) is a gigantic mosaic CCD camera, which is attached at the prime focus of Subaru Telescope. The HSC uses 104 main science CCDs, which covers 1.5-deg field-of-view in diameter with a pixel scale of 0.17 arcseconds, as well as 4 CCDs for auto guider, and 8 CCDs for focus monitoring.

It takes about 30 min for changing filters (including a focus check). When we exchange filters, it is necessary for us to move telescope to the zenith position, and rotate the instrument rotator to the appropriate angle. we also close the cover of the primary mirror for safety operation.

When you cosider to produce new HSC filters, please read the filter policy carefully, and contact Subaru Telescope (contact person: T. Terai [terai_at_naoj.org]) well before applying for funds. Also, please refer the procedure to determine filters for each HSC run.

We ask for your understanding in advance that observed data, whose proprietary periods (1.5 yrs) do not end, may be used by Subaru staff without PI's permission for engineering purposes.



Data Analysis


Image Quality

Problem Reports


Questions regarding HSC should be directed to Dr. Satoshi Miyazaki (satoshi_at_naoj.org), Dr. Fumiaki Nakata (nakata_at_naoj.org) and/or Tsuyoshi Terai (terai_at_naoj.org).

Please note that all numbers on these pages are subject to change as the performance of HSC is better determined.

Last update: March 20, 2021

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